For the sauce: - Unsalted butter - All purpose flour - Garlic powder - Black pepper - Kosher salt - Whole milk - Unsalted chicken stock - Heavy cream
Make the sauce in a Dutch oven or large pot by first melting the butter over medium heat. Once the butter is melted, whisk in the all-purpose flour, garlic powder, black pepper, and salt.
Stir in the cooked penne pasta and shredded chicken until everything is coated in the cream sauce. Add half the pasta mixture to the prepared 9×13 baking dish.